QVAVC Codec Troubleshooter

Video Transmission Problems

(Transmission from QVAVC Encoder to QVAVC Decoder)

· No Video

1. Click on Network/Ping on Encoder and try to ping decoder

* If ping fails, check network connectivity

2. Check Status on Encoder. Do you see a non-zero bitrate? If Yes, go to 3.

* If bitrate is zero or blank, check for a valid video source or that the correct input has been selected.

* For SDI input, make certain that it has embedded audio

* For HD-SDI without embedded audio, enable “Use Analog Audio for HD Video” under Advanced Profile

* For HDMI input, make certain that the source is HD. The HDMI input will not work with SD video. Also, make certain that you see a green HDMI Lock light on the front of the codec. If it is off, then the codec cannot sync to the HDMI source.

* Check the video source resolution. The QVAVC Codec can only encode the following input video resolutions: 1080i, 720p, 576i, and 480i. You must insure that the input is one of these formats for encoding to start.

3. Check status on Decoder. For a zero bitrate:

* If there is a firewall, check that the video UDP port is forwarded to the codec. The default UDP video port is 10000.

4. If the incoming bitrate at the decoder is zero (0):

* Please remember that to send video over the Internet, you cannot use the local 192.168.XXX.YYY address. Any IP address beginning with 192 is a private address, and cannot be directly used over the public Internet. Most Internet connections are through a Firewall. You must set up Port Forwarding, or Network Address Translation (NAT) so that when you send the video stream from your encoder, you can use the public IP address of the firewall, and have the firewall forward those packets to the decoder. Please see your network administrator for further help in setting up your firewall to enable port forwarding to the decoder.

* If you are using ARQ error correction, we suggest that you set the ARQ port and the video UDP port to the same value (if you are not using server mode) so that you can avoid setting up port forwarding for the ARQ retransmission request packets on the encoder-side firewall.

5. If the decoder shows a non-zero network bitrate, then check that you are using the correct video output. HDMI ONLY outputs HD video. Composite ONLY outputs SD video. (SDI can output either SD or HD video.)

· Video Freezes/Pauses

1. Check Status on Decoder. Is the Network Packet Loss non-zero?

* If you have packet loss, then enable ARQ packet loss on encoder and decoder

* If ARQ Recovered is always zero, yet the number of ARQ Retransmission Requests is non-zero, then check that the ARQ UDP port is opened upstream on the encoder (default is UDP port 7020).

* If ARQ is enabled, increase Target Latency

2. In no packet loss, then try disabling ARQ on decoder and restart

* ARQ on decoder cannot handle bitrates higher than 5 Mbps

3. If problem persists, then try increasing Video Buffer Size

* Excessive network jitter can affect decoder output

4. If problem persists, enable Detect Video Break, save, and power-cycle decoder

* Without this feature enabled, the decoder can get into a bad state when the encoder is restarted

* Sometimes, this requires power-cycling for proper operation. Enabling Detect Video Break will prevent problems in the decoder. Enabling Detect Video Break will cause the decoder to restart when it looses video for more than 1.5 seconds or when the encoder is restarted. The decoder takes about 1 second when it restarts and may produce a green flash on the output.

· Video Color Distortion

1. If using SDI or HDMI input, try enabling Resync SDI or Resync HDMI, respectively, under Advanced Profile settings and restart encoder.

2. Has the video source been previously encoded with a 4:2:0 encoder? If so, then successive encoding and decoding will degrade the color or result in "grainy" or fuzzy video.

3. If the "Video Buffer Size" parameter on the decoder is too small, the decoder can lose sync for certain types of video content, resulting in black and white video or video with severe color distortion. To remedy this, please try increasing the "Video Buffer Size" on the decoder to 500 ms, save the new setting and restart the decoder.

4. If problem persists, check video source.

· Other Video Distortion, Blurriness, or Pixelation

* Try increasing video bitrate on encoder.

* Insufficient encoding bitrate can cause blurrier video, pixelation of the image for high-motion content.

· Low Latency Mode: Minimizing End-to-End Delay

* Set the following parameters on encoder:

On Basic Encoder Profiles: Set IP Transport = UDP

On Advanced Encoder Profiles: Set Remux Mode = Offline, Low Delay = y, B-Frames = 0, P-Frames = 14

Use 720p Video Format for Video Input

* Set the following parameters on decoder (must be version 109 or greater):

On Video Decoder Profiles: Set Low Delay = y, Video buffer size = 100

On Network Decoder Profiles: Set IP Transport = UDP

Set output resolution = 720p